(Invited) Luminescent InP Quantum Dots: They're Not Just Like CdSe

Abstract

There are significant similarities and differences in the spectroscopy and photophysics between CdSe-based and InP-based quantum dots. One of the more important differences is the presence of reversibly populated hole traps in InP/ZnSe quantum dots (QDs). These traps affect many aspects of the overall excited state dynamics. In this paper we elucidate the hole relaxation dynamics in high quality InP/ZnSe/ZnS QDs at room temperature and focus on the role of these traps. Specifically, we show that the presence of transiently populated traps results in extremely slow (tens of picoseconds to nanoseconds) hole cooling as evidenced by a significant fraction of the photoluminescence exhibiting a slow risetime following photoexcitation. Through a combination of chemical derivatization studies and density functional theory calculations, they are assigned to substitutional indium adjacent to a zinc vacancy, In3+/VZn 2-, in the ZnSe shell.